Apparatus for collecting suspended particles



April 23, 1957 H. A. WINTERMUTE 2,789,658

APPARATUS FOR COLLECTING SUSPENDED PARTICLES Filed June` 22, 1955 4Sheets-Sheett 1l fir g Il 0 I "l'llll'l'l- I u m w n 4 l INVENTOR [l/VRHARRY A. vyiNTERMuTE ATTORNEY April 23, 1957 H. A. WINTERMUTE AFFRTUSFR` COLLECTING SUSPENDED PARTICLES 4 Sheets-Sheet 2 Filed June 22, 1955Nmk OMM INVENT OR HARRY A. WINTERMUTE ATTQRNEY April 23, 1957 H. A.wjNTERMUTE 2,789,658

APPARATUS FOR COLLECTING SUSPENDED PRTICLES Filed June 22, 1955 4sheets-snee: s

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April 23, 1957 H. A. WINTERMUTE 2,789,658

APPARATUS FOR COLLECTING SUSPENDED PARTICLES Filed June 22, 1955 4Sheets-Sheet 4 Erg- Z.

, INVENTOR HARRY A. wmTERMuTs ATTORNEY APPARATUS EUR COLLECTINGSUSPENDED 1 PARTICLES Harry A. Wintermute, Plainfield, N. Il., assignorto Research Corporation, New York, N. Y., a corporation ofNew YorkApplication lune 22, 1955, Serial No. 517,170

4 Claims. (Cl. 18S-7) This invention relates to electrical precipitationapparatus and more particularly and specifically apparatus for combiningmagnetic and electrostatic fields for the collection of a suspendedparticulate material.

lt has been discovered in passing liuc gases and the like throughelectrostatic precipitators a portion of the particles suspended in thegas that possess magnetic properties, such as, for example, thoseparticles containing magnetite, hematite, limonite, pentlandite andwolframite, tend to move out into the gas stream within the precipi atormore readily than other particles thereby reducing the effectiveness andetiiciency of the precipitator.

It has also been discovered that by magnetizing the collectingelectrodes of an electrostatic precipitator, the electrodes will moreeffectively hold dust patricles having magnetic properties after theyhave been precipitated thus reducing the percentage of dust particlespassing through the precipitator and thereby increasing the efflciencyand effectiveness of the gas cleaning apparatus.

lt is therefore a principal object of this invention to provideapparatus for combining magnetic fields and electrostatic fields toeffectively increase precipitator efficiency when handling gases havingsuspended therein dust particles of magnetic susceptibility.

Another object of this invention is to provide new and improvedelectrostatic precipitator construction which `includes magnetizedcollecting electrodes to provide a magnetic eld between electrode facestransversely of the path and perpendicular to the direction of gas flowin the precipitator.

A further object of this invention is the provision of new and improvedelectrostatic precipitation apparatus including electro-magnetizedelectrodes creating magnetic fields in the path of gas flow through theprecipitator.

Still another object of the present invention is the provision of newand improved electrostatic precipitator apparatus including permanentmagnetic structures associ ated with the collecting electrodes of theprecipitator which create magnetic fields across the path of gas ow inthe precipitator.

A still further object and advantage of this invention is the provisionof new and improved electrostatic pre cipitation apparatus forestablishing magnetic fields between the collecting electrodes andacross the path of gas ow within the precipitator which is readilyadapted to construction of precipitators wherein the charging andprecipitation of dust particles is simultaneous, as well as toprecipitator constructions in which the particles are precharged beforeentering the collector section of the precipitator.

Still further objects and advantages of the present invention willbecome readily apparent to those skilled in the art when theaccompanying drawings are read in the light of the following generalstatement and description.

The nature of the presen! invention may be stated in general terms asconsisting of a new and improved particle collecting apparatus includinga shell. a gas inlet, a gas outlet, spaced collecting and dischargeelectrodes suspended within the shell in the path of gas ow between' theinlet and the outlet, and means associated with said collectingelectrodes establishing a magnetic field between the surfaces ofadjacent electrodes.

Referring now to the accompanying drawings in which like numeralsdesignate similar parts throughout the several views:

Fig. l is a vertical section through a precipitator em'd bodying oneform of the construction constituting the present invention.

Fig. 2 is a horizontal section taken on line 2 2, Fig. l.

Fig. 3 is a vertical section taken on line 33, Fig. l.

Fig. 4 is a view similar to Fig. 2 showing a modified form of theinvention.

Fig. 5 is a horizontal section illustrating a still further modificationof the present invention.

Fig. 6 is a view similar to Fig. 5 showing a modification of the form ofthe invention illustrated in Fig. 5.

Figs. 7 is a fragmentary, pictorial View of a modified electrodeconstruction embodying the principles of the present invention.

In Figs. l-3 of the drawings there is illustrated a twopasselectrostatic precipitator in which the charging and collecting of dustparticles takes place in the same zone. The numeral 10 designates theprecipitator shell which is provided at one end thereof with a gas inlet12 and at the otherend with a gas outlet 14. The shell 10 is dividedlongitudinally into two sections 16 and 18, each of which is` providedwith a hopper bottom 20 for the collection and discharge of precipitatedmaterial.

Additionally, each of the shell sections 16 and 18 of the precipitatoris provided, in the instant embodiment of the invention, with identicalelectrostatic precipitating apparatus, generally designated at 22, intowhich is incorporated the unique and useful magnetic collectionapparatus which constitutes, in combination with the electrostaticapparatus, the primary concept of this invention.

Because of the similarity between the combined electrostatic-magneticprecipitator apparatus contained in each of the two pass sections 16 and18 ofthe precipitator shell, only that apparatus supported in the secondpass section, 18, will be described hereinafter in detail.

In section 18 of the two-pass precipitator shell 10 a typical hightension electrode supporting frame 24.is suspended from insulatedmountings 26 on the shell to lie horizontally in the upper region of thesection and from which are supported in the usual manner a plurality ofspaced, parallel rows of discharge electrodes 28, the lower ends ofwhich are secured in the lower region of the shell section in a loweraligning Vframe 30.

A plurality of collecting electrodes 32 of the tiat plate type andconstructed of iron or other magnetic material are supported from a pairof suitable end frame members 34 to extend longitudinally of the shellsection in parallel spaced relationship, each plate also extending inparallel spaced relationship between and equally spaced from adjacentrows of the discharge electrodes 2S suspended from the frame 24, as isbest illustrated in Fig. 2. Associated with each of the collectingelectrode plates 32 are battlesthese plate bafes may be constructed ofnon-magnetic orA magnetic material.

The structures described above provide an electrostatic ,I

precipitator wherein flue gases passing around the discharge electrodesand between adjacent, spaced collecting electrodes is subjected to anelectrostatic field inducing Patented Apr. 23,195?

suspended particles in the gas to be precipitated on the` In addition tothe foregoing, however, the adjacent ends of each of theadjacentcollecting electrodesfare interconnected at spaced intervalsvertically ofthe heightof the ends of, said collecting plates bypermanent magnets 38 which are of` substantially U-shapedcontigurationin plan view and which are secured laterally of the electrode plateseries with like polesv in each adjacent' pair of magnets laterally ofthe apparatusV being disposed. in end to end opposition as illustrated.

By this foregoing application of permanent magnets-secured between theends of the collecting electrodes of an electrostatic precipitatorstructure, a magnetic eld is established between the opposed surfaces ofadjacent col'- lecting electrode plates 32 in the precipitator whichmagnetic ields extend transversely of the direction of gas iiow throughthe precipitator thereby inliuencing suspended particles in the gas.stream having magnetic susceptibility causing them to be held bymagnetic attraction upon the plate surfaces of the collecting electrodesrather than moving into the gas stream and passing through theprecipitator. i

Referring to Fig. 4 of the drawings there is shown a modification of theaforedescribed embodiment of the present invention wherein the permanentmagnets employed between the ends of adjacent magnetizable collectingelectrode plates are replaced by a magnetic yoke 40 which includes apair of'arms 42, each arm of each pair extends across the ends of thecollecting electrodes 32 and are interconnected by a yoke bar 44 aroundwhich is provided a coil 46 connected to a source S of alternatingcurrent with one side of the line connected to said source through arectier 48 which is shunted by a resistance 50.

Each of the collecting electrode plates 32 in this electromagneticstructure is shorter than the span between the two parallel arms 42 ofthe magnetic yoke, and the plates 32 are alternately arrangedtransversely of the precipitator lwith one end anchored to one of theyoke arms 42 and with the second end secured to a non-magnetic insert 51which in turn is supported by the yoke arm 42 opposite that to which theplate end is secured. By this arrangement the opposite ends of adjacentcollecting plates are secured to opposed arms 42 of the electro-magneticyoke whereby north and south polarity is established between adjacentplates to create a magnetic eld between the opposed surfaces of theadjacent plates in the pref5() cipitator construction.

In this construction magnetic fields are established between the opposedsurfaces of adjacent collecting electrodes in much the same manner asheretofore described relative to the permanent magnetic arrangement withthe shunt resistance in the coil source supplying a small amount ofreserved tlow magnetism to the fields for the purpose of counteractingresidual, and/ or to aid in the residual magnetic action on the dustparticles in the gas flow.

ln utilizing the electro-magnetic apparatus described above it has beenfound necessary in precipitators having shells formedy of magneticmaterial to break the continuity of the shell into separated sections asat 52 interposing in the broken sections closures of non-magneticmaterial 54 in the region of the precipitation apparatus. Likewise,non-magnetic inserts 56 must necessarily be made in the shell at thosepoints where the magnetic yoke arms 42 extend through the shell wall tobridge the ends of the collecting electrodes.

Referring now to Fig. 5 of the drawings there is illustratcd ahorizontal section through a fragment` of a typical electrostaticprecipitator construction in which there are separate charging andcollection sections within the precipitator and through which the gasflows in the order stated from the gas inlet ofthe precipitator to theoutlet.

In this construction there is located within the precipitator shell 58 aplurality of parallel spaced collecting electrode plates 60 which aremaintained at ground potential together with a plurality of parallelspaced collecting electrode plates 62 which lie alternately inequidistant intervals between and parallel with collecting plates 60.Plates 62 are insulated and maintained at a potential above that ofplates 6); As in the previously disclosed form of the invention, all ofthe plates extend longitudinally of the shell and the plates 60 are of agreater length than,

they .plates 62 so that their ends terminate at a spaced distance beyondeach end of the intermediate plate 62.

Located on the gas inlet side of the collecting plate structure abovedescribed are a plurality of tubular grounded electrodes 64 which extendvertically within the shell at equally spaced intervals transversely ofthe path of gas cw from the gas inlet to the collection plates. Locatedintermediate the grounded electrodes 64, and the collting platestructure are a plurality of ionizing electrodes 66, such as rods orwires. vertically within the shell at spaced intervals transversely ofthe shell and the gas ilow therein with the lateral spacing of theionizing electrodes being the same as that ofj the groundedl electrodes64 to provide a charging field 68 between each of the ionizingelectrodes and the wo adjacent grounded electro-des 64. With this formof construction gas flowing from the inlet to the collection sect tionof the precipitator passes through charging lie1dsf68, ,f

established between the grounded and the ionizing electrodes inthecharging section whereby the dust particles suspended in the gas areionized beforeV they enter the collecting section of the precipitator.

in' :this form of the invention, the adjacent ends of ad-g jacentcollecting electrode plates 60 are interconnected by permanent magnetswhich are of the same construction Yand which are securedy in place'andlocated in the same manner as magnets 38 described relative .to thevform of the invention illustrated in Fig. 2. The perma-- nent magnetsestablish magnetic fields between the opposed surfaces of adjacentplates 6i) and the insulated plates 62 are magnetized with the surfacesthereof asi-l suming polarities opposite to the polarities of thesurfaces of the plates 6l! which they oppose. In this construction, i

the collection plates, and the collection section of them precipitatorwhereby collected magnetizable mttrial is readily held to the platesurfaces.

.In Fig. 6 of the drawings there is illustrated a modified form of theinvention as disclosed in Fig. 5 wherein an electro-magneticconstruction is incorporated to replace the permanent magnets previouslydescribed. In this= modification non-magnetic inserts 72 are made in theprecipitator shell 58 in the same manner las inserts 54 and 56 were madein the construction illustrated in Fig. 2, and an electro-magneticconstruction including yoke arms 74, a yoke' coil '76, yoke bar 78, andnon-magnetic insert sections 79 are substituted for the permanentmagnets 7) in the same manner as the electro-magnetic structureillustrated in Fig. 4.

In Fig. 7 of the drawings there is illustrated a further modiedconstruction of an electrostatic precipitation apparatus including meansfor establishing magnetic fields between the opposed surfaces ofadjacent collecting electrodes. In this form of the invention aplurality of grounded collecting plates S2, of magnetic material, arearranged in conventional parallel spaced, relationship.

All oftheplates in the series constituting the collecting electrodeassembly are interconnected by permanent, cylindrical magnets 8S whichinterconnect the opposed y surfaces ofLadjacent plates and which aresupported in their interconnecting positions by non-magnetic rods orbolts 96a which, extend tlntnigh `aligned openings 92 in These rods aresecuredarsasa :arranged in any spaced pattern longitudinally andvertically of the plates as is necessary to establish magnetic fieldsbetween the opposed surfaces of the plates to the desired intensity.

By this foregoing construction magnetic flux distribution over thesurfaces of the collectingelectrode plates within the precipitatorapparatus is provided for the accomplishment of the same purposes andfunctions as has heretofore been set forth relative to the earlierdescribed embodiments.

By the heretofore described constructions precipitator apparatus hasbeen disclosed which includes magnetic fields provided between opposedsurfaces of adjacent collecting plates within the apparatus whichmagnetic fields will have a limited tendency to supplement theelectrostatic precipitation of magnetic susceptible particles suspendedin a gaseous medium passed adjacent the plates, and which will have adecided function to produce a hold-ing force on these precipitatedparticles holding them to the collecting plates by magnetic attractionand thereby decreasing the portion of particles escaping through theprecipitator with the gas stream.

It is, of course, understood that the magnetic holding force on thesurfaces of the collecting electrode plates within the precipitatorapparatus can be of varied tenacity dependent in part on the magneticsusceptibility of the particles suspended within the gas as well as uponthe physical construction of the apparatus with regard to the strengthof the magnets utilized, the number of magnets, the specific spacing andpatern arrangement of magnets, the magnetic characteristics of thematerial constituting the collecting plates, the thickness of theplates, and the distance between adjacent collecting plates within theapparatus.

Accordingly, it is seen that apparatus has been dis closed whichefficiently and effectively establishes a magnetic field across the pathof gas flow through an electrostatic precipitator and which for thepurpose of accomplishing the objects and advantages heretofore set forthand for the purpose of enabling practice of a new and improved method ofprecipitation which includes the steps of passing a flow of gas throughan electrostatic field, over the surfaces of charged collectingelectrode plates, and through magnetic fields extending perpendicular tothe path of gas flow, discharging the gas, and collecting dust particlesprecipitated in the electrostatic field on collecting electrode plates,and holding said particles on the collecting plates by magneticattraction.

Thus having described and explained the construction and operation ofthe present invention and the new and useful results obtained by thepractice thereof, what is having a gas inlet and a gas outlet spacedfrom the gas inlet, a plurality of parallel extended surface collectingplate electrodes positioned in said casing with the extended surfacesthereof positioned parallel to the flow of gas from the inlet to theoutlet, a plurality of high voltage electrodes interspaced between theparallel collecting plate electrodes, means establishing electrostaticfields between the high voltage electrodes and the collecting plateelectrodes and means establishing magnetic elds between the opposedsurfaces of the collecting electrodes, whereby materials suspended in agas stream are simultaneously subjected to both electrostatic andmagnetic fields existing at right angles to the direction of the gasflow through the casing.

2. Precipitation apparatus as defined in claim 1 wherein permanentmagnets are secured between the adjacent ends of adjacent collectingelectrode plates at spaced intervals along the length of the ends ofsaid plates; whereby magnetic fields are established between the opposedsurfaces of adjacent collecting electrode plates which magnetic fieldsextend transversely of the path of gas flow through the precipitator andbetween the plates.

3. Precipitation apparatus as defined in claim 1 whereinelectro-magnetic means interconnect the ends of adjacent collectionelectrode plates at spaced intervals along the lengths of the ends ofsaid plates; whereby magnetic fields are established between the opposedsurfaces of adjacent collecting electrode plates which magnetic fieldsextend transversely of the path of gas ow through the precipitator andbetween the plates.

4. Precipitation apparatus as defined in claim 1 including magneticmeans interconnecting the ends of adjacent collecting electrode platesat spaced intervals along the lengths thereof, whereby magnetic fieldsare established between the opposed surfaces of adjacent collectingelectrode plates.

References Cited in the le of this patent UNITED STATES PATENTS 977,570Sutton et al. Dec. 6, 1910 1,949,660 Roberts Mar. 6, 1934 FOREIGNPATENTS 67,421 Sweden Oct. 25, 1927 683,488 France Mar. 3, 1930

